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Unpredicted spontaneous extrusion of a renal calculus in an adult male with spina bifida and paraplegia: report of a misdiagnosis. Measures to be taken to reduce urological errors in spinal cord injury patients

Abstract

Background

A delay in diagnosis or a misdiagnosis may occur in patients with spinal cord injury
(SCI) or spinal bifida as typical symptoms of a clinical condition may be absent because
of their neurological impairment.

Case presentation

A 29-year old male, who was born with spina bifida and hydrocephalus, became unwell
and developed a swelling and large red mark in his left loin eighteen months ago.
Pyonephrosis or perinephric abscess was suspected. X-ray of the abdomen showed left-sided
staghorn calculus. Since ultrasound scan showed no features of pyonephrosis or perinephric
abscess, he was prescribed a prolonged course of antibiotics for infection presumed
to arise from the site of metal implant in spine. He developed a discharging sinus,
following which the loin swelling and red mark subsided. About three months ago, he
again developed a red mark and minimal swelling in the left loin. Ultrasound scan
detected no abnormality in the renal or perinephric region. Therefore, the red mark
and swelling were attributed to pressure from the backrest of his chair. Five weeks
later, the swelling in the left loin burst open and a large stone was extruded spontaneously.
An X-ray of the abdomen showed that he had extruded the central portion of the staghorn
calculus from left kidney. With hindsight, the extruded renal calculus could be seen
lying in the subcutaneous tissue of left loin lateral to the 10th rib in the X-ray of abdomen, which was taken when he presented with red mark and
minimal swelling.

Conclusion

This case illustrates how mistakes in diagnosis could occur in spinal cord injury
patients, and highlights the need for corrective measures to reduce urological errors
in these patients. Voluntary reporting of urological errors is recommended to facilitate
learning from our mistakes. In the patients who have marked spinal curvature, ultrasonography
of kidneys and perinephric region may not be entirely reliable. As clinical symptoms
and signs may be non-specific in SCI patients, they require prompt, detailed and occasionally,
repeated investigations. A joint team approach by health professionals belonging to
various medical disciplines, which is strengthened by frequent, informal and honest
discussions of a patient's clinical condition, is likely to reduce urological errors
in SCI patients.

Background

A delay in diagnosis or a misdiagnosis may occur in the patients with spinal cord
injury (SCI) or spinal bifida as typical symptoms of a clinical condition may be absent
in these patients because of their neurological impairment. [1]. Physicians may commit an error in diagnosis of a clinical condition as the symptoms
and signs may be non-specific [2], or mistakes could occur during interpretation of medical images or histological
appearances. Atypical decubital fibroplasia [3], which is a unique type of pressure sore displaying degenerative and regenerative
features distinct from decubitus ulcer, may be misdiagnosed by pathologists and clinicians
as a sarcoma. Epidemiology of medical errors showed that patients aged over 64 years
have a greater risk of serious injury from adverse events than younger patients. [4]. We believe that patients with spinal cord injury and spina bifida should be included
in the high-risk group for possible occurrence of medical errors. We report an adult
with spinal bifida and paraplegia, who presented with redness and minimal swelling
in the loin. This was diagnosed initially as a pressure mark. Subsequently, a large
renal calculus was extruded out of the loin swelling spontaneously.

Case presentation

Case report

A 29-year old male, who was born with spina bifida and hydrocephalus, presented recently
with recurrent episodes of redness and minimal swelling in the left loin. At the age
of eight years, he had an ileal conduit urinary diversion and surgery for kyphoscoliosis.
An intravenous pyelography performed five years ago showed bilateral renal calculi
(left greater than right). Right kidney was functioning, but no contrast was seen
in the left pelvicalyceal system or ureter. Eighteen months ago, he became unwell
and developed a swelling and large red mark in left loin. Pyonephrosis or perinephric
abscess was suspected. X-ray of abdomen showed left-sided staghorn calculus. There
was a small stone in the right kidney. (Figure 1). Ultrasonography revealed no evidence of hydronephrosis. Since ultrasound scan showed
no features of pyonephrosis or perinephric abscess, he was prescribed prolonged course
of antibiotics for infection presumed to arise from the site of metal implant in spine.
He developed a discharging sinus following which, the loin swelling and red mark subsided.

Figure 1. X-ray of abdomen (05052000): This X-ray of abdomen shows large staghorn calculus in
the left kidney and a small stone in right kidney.

About three months ago, he again developed a red mark and minimal swelling in the
left loin. He did not have fever. Blood tests were not done during this visit. However,
blood tests were performed five days later. The results were as follow: Haemoglobin:
7.0 g/dL; White cell count: 12.6 x 109/L; Neutrophils: 10.37 x 109/L. Urea: 14.2 mmol/L;
Creatinine: 199 umol/L; C-reactive protein (CRP): 171.4 mg/l. In view of elevated
white cell count and high CRP level, the general practitioner was requested to prescribe
antibiotic. Patient received amoxicillin 250 mg every eight hours by mouth. X-ray
abdomen showed left-sided staghorn calculus. (Figures 2 and 3). Ultrasonography showed no evidence of hydronephrosis. Since ultrasound scan detected
no abnormality in the renal or perinephric region, the red mark and swelling were
attributed to pressure from backrest of his chair. About five weeks after the radiological
examination, the swelling in left loin burst open and a large stone was extruded spontaneously.
(Figure 4). Following spontaneous extrusion of renal calculus, the sinus became smaller. (Figure
5). There was minimal discharge of seropurulent fluid. An X-ray of abdomen showed that
he had extruded central portion of the staghorn calculus from left kidney. (Figure
6). With hindsight, the extruded renal calculus could be seen lying in the subcutaneous
tissue of left loin lateral to the 10th rib in the X-ray of abdomen, which was taken when he presented with red mark and
minimal swelling (Figures 2 and 3). This radio opaque density situated in the soft tissue of left loin was not present
in either of the X-ray of abdomen taken earlier (Figure 1) or subsequent to extrusion of the renal calculus. (Figure 6).

Figure 3. A close-up view of left lumbar region in the X-ray of abdomen A large stone is seen
lying in the soft tissue of left loin lateral to the 10th rib.

Figure 4. Photograph of the stone Renal calculus, which was extruded spontaneously through the
loin, is shown.

Figure 5. Clinical photograph of left loin This photograph shows a sinus in left loin through
which the central portion of a staghorn calculus was extruded spontaneously.

Figure 6. X-ray of abdomen (13112001) This abdominal X-ray shows the radio opaque shadow previously
located in left loin is no longer present.

Discussion

Breatnach and associates [5] reported spontaneous extrusion of a staghorn calculus into the flank soft tissues,
which was diagnosed by CT. The stone was demonstrable on CT as fragments of calciflc
density appearing in the subcutaneous area. Breatnach and associates [5] stated that such a complication of renal calculus disease has not been reported previously.
We failed to detect the calculus lying in the soft tissue of left loin in an abdominal
X-ray (Figure 3), when this patient presented with redness and swelling in left loin. The ultrasound
scan showed no abnormality in the kidney or perinephric region. Unfortunately, we
did not evaluate the loin wall during this ultrasound examination. We attributed the
swelling and redness to pressure caused by backrest of his chair, since SCI patients
are highly susceptible to develop pressure sores. Instead of making a presumptive
diagnosis of pressure mark, we should have persevered in our diagnostic efforts and
should have reviewed the X-rays of abdomen, which were taken at different times. Obviously,
there was an over reliance on the ultrasound scans. In hindsight, we realise that
should have performed a CT of abdomen. Had we carried out a CT of abdomen, we would
have detected the extruded stone lying in the subcutaneous tissue, and reached the
correct diagnosis of spontaneous extrusion of renal calculus.

What should we do to reduce urological errors in the patients with spinal cord injury?

Voluntary reporting of urological errors will be helpful to facilitate learning from
our mistakes or near miss: A recent report from the Institute of Medicine, To Err is Human, strongly recommends complementary mandatory incident reporting systems and voluntary
near miss reporting systems in health care. [6]

SCI patients require prompt, detailed and if necessary, repeated investigations as
clinical symptoms and signs may be non-specific in SCI patients. Absence or paucity
of typical symptoms and signs in SCI patients is well illustrated by this case. This
paraplegic patient, who developed perinephric abscess and extruded central portion
of a staghorn calculus, did not develop loin pain at all.

SCI patients are susceptible to develop certain clinical conditions and diagnosis
of these disorders may not be easy. A few examples pertaining to urinary tract of
SCI patients are given below:

♦ In SCI patients, renal calculi may be obscured by bowel gas shadows or by loaded
colon in a plain X-ray of abdomen. Ultrasonography of kidneys and perinephric region
may be unreliable in SCI patients who have marked spinal curvature. Even CT may be
distorted by the patient's spinal and pelvic deformity and true axial images may not
be obtained; this can make definition of soft tissue planes difficult.

♦ SCI patients are at increased risk for developing bladder cancer. When vesical malignancy
occurs, SCI patients may not always present with the classical symptom of haematuria.
Cystoscopy, when performed to screen for squamous cell cancer of the bladder in spinal
cord injured patients with chronic or recurrent urinary tract infection, has been shown to result in an earlier stage at diagnosis and convey a survival advantage.
[7]

♦ Histological interpretation of bladder biopsies in SCI patients may be difficult
because of associated inflammatory changes. Immunohistochemistry of urinary bladder
biopsy, in addition to routine haematoxylin & eosin staining, may be a useful diagnostic
aid in selected SCI patients. Immunostaining with cytokeratin 14 may help in early
detection of squamous metaplasia.

Immunostaining with Cytokeratin 20 is likely to facilitate the diagnosis of urothelial
dysplasia. [8]

♦ When the result of a diagnostic procedure is at variance with the overall clinical
probability, a repeat investigation might be useful, particularly in SCI patients,
as these patients do not manifest typical symptoms and signs. A patient, who had sustained
spinal cord injury and paraplegia 36 years ago, presented with recurrent urinary infection.
He did not give a history of haematuria. A bladder biopsy showed features of inflammation
and papillary cystitis. There was no evidence of dysplasia or neoplasia in this biopsy.
(Figure 7). However, a repeat bladder biopsy, which was performed three weeks later, revealed squamous cell carcinoma. (Figure
8).

Figure 7. A male patient sustained spinal cord injury and paraplegia 36 years ago. He presented
with recurrent urinary infection. There was no history ofhaematuria. Histology of
bladder biopsy shows moderately inflamed bladder mucosa and papillary cystitis. There
was no evidence of dysplasia or neoplasia in this biopsy. (HP01/06270)

Figure 8. Photograph of repeat bladder biopsy in the same patient as in Figure 7. A second bladder biopsy was performed three weeks later. This biopsy revealed keratinising,
moderately differentiated invasive, squamous cell carcinoma. (HP01/07168)

SCI patients may develop clinical problems, which affect different organ systems
and require investigations by physicians with expertise in their specialities, e.g.
imaging studies by radiologists, histopathological examination of biopsies, gastrointestinal
or, urinary tract endoscopy. Therefore, health professionals working in various disciplines
should remove artificial barriers and hierarchical settings, which exist to varying
degrees in healthcare system, and hold frequent, informal and honest discussions of
a SCI patient's clinical condition. Such a joint team approach in reaching a diagnosis,
and in implementing a treatment regime, is likely to reduce medical errors in SCI
patients.

Conclusions

SCI patients require detailed and sometimes, repeated investigations as clinical symptoms
may be vague and clinical signs could be completely non-specific. We missed an underlying
renal pathology in a paraplegic patient, who presented twice with loin swelling and
redness. There was a delay in making a correct diagnosis because of our total reliance
on the report of ultrasound scans, which failed to detect the perinephric lesion in
this paraplegic patient with spinal curvature. We learn from this case that ultrasonography
of kidney and perinephric region may not be completely reliable in SCI patients, who
have marked curvature of spine. A joint team approach by health professionals belonging
to various medical disciplines, which is strengthened by frequent, informal and honest
discussions of a patient's clinical condition, is likely to reduce urological errors
in SCI patients and improve the quality of their care.

Competing interests

All authors are associated with the provision of medical care to SCI patients. Therefore,
the authors sincerely wish to reduce medical errors in spinal cord injury patients.

Acknowledgement

We thank the patient for providing written consent for publication of the clinical
photograph.